capistrano-spec 0

Capistrano… the final frontier of testing… well, maybe not final, but it is a frontier. I had set out to do some bug fixing and some BDDing on some of my capistrano code, but found it wasn’t really obvious how to do so. As a result, I set out to write capistrano-spec and document how to test capistrano libraries.

== Install

You know the drill:

gem install capistrano-spec

And require it in your +spec/spec_helper.rb+:

require ‘capistrano-spec’

== Designing your capistrano extension

In the wild, you’ll mostly commonly come across two patterns:

files living under recipes/* that are autoloaded

files living under lib that are required from config/deploy.rb

In these files, you can start using the capistrano top-level methods, like +namespace+ or +task+, like:

# in recipes/speak.rb or lib/speak.rb
task :speak do
set :message, ‘oh hai’
puts message
end

Capistrano does some trickery to +require+ and +load+ so that if you +require+ or +load+, the file is ran in the context of a Capistrano::Configuration, where all the +task+ and +namespace+ methods you know and love will be available.

Some consider this a little gross, because it’d be easy to accidentally require/load this without being in the context of a Capistrano::Configuration. The answer to this is to pull use +Capistrano::Configuration.instance+ to make sure it’s evaluted in that context:

# in recipes/speak.rb or lib/speak.rb
Capistrano::Configuration.instance(true).load do
task :speak do
set :message, ‘oh hai’
puts message
end
end

There’s a problem though: it’s not particular testable. You can’t take some +Capistrano::Configuration+ and easily bring your task into it.

So, here’s what I recommend instead: create a method for taking a configuration, and adding your goodies to it.

require ‘capistrano’
module Capistrano
module Speak
def self.load_into(configuration)
configuration.load do
task :speak do
set :message, ‘oh hai’
puts message
end
end
end
end
end

# may as well load it if we have it
if Capistrano::Configuration.instance
Capistrano::Speak.load_into(Capistrano::Configuration.instance)
end

Now, we’re going to be able to test this. Behold!

== Testing

Alright, we can start testing by making Capistrano::Configuration and load Capistrano::Speak into it.

describe Capistrano::Speak, “loaded into a configuration” do
before do
@configuration = Capistrano::Configuration.new
Capistrano::Speak.load_into(@configuration)
end

end

Now you have access to a configuration, so you can start poking around the [email protected]+ object as you see fit.

Now, remember, if you +set+ values, you can access them using +fetch+:

before do
@configuration.set :foo, ‘bar’
end

it “should define foo” do
@configuration.fetch(:foo).should == ‘bar’
end

You can also find and execute tasks, so you can verify if you successfully set a value:

describe ‘speak task’ do
before do
@configuration.find_and_execute_task(‘speak’)
end

it "should define message" do
@configuration.fetch(:message).should == 'oh hai'
end

end

One thing you might be wondering now is… that’s cool, but what about working with remote servers? I have just the trick for you: extensions to Capistrano::Configuration to track what files were up or downloaded and what commands were run. Now, this is no substitution for manually testing your capistrano recipe by running it on the server, but it is good for sanity checking.

before do
@configuration = Capistrano::Configuration.new
@configuration.extend(Capistrano::Spec::ConfigurationExtension)
end

it “should run yes” do
@configuration.run “yes”
@configuration.should have_run(“yes”)
end

require ‘capistrano’
module Capistrano
module Speak
def self.load_into(configuration)
configuration.load do
before “deploy:finalize_update”, “foo:bar”
namespace :foo do
task :bar do
set :message, ‘before finalize’
puts message
end
end
end
end
end
end

it “performs foo:bar before deploy:finalize_update” do
@configuration.should callback(‘foo:bar’).before(‘deploy:finalize_update’)
end